Question

I’m using a WCF Service in which I would like to respond with a list of objects. As my objects are generated by entity framework, I can’t really return a List as it has some circular references and default serialization fails. Thus, I’m using anonymous types to create a list of objects containing only the properties I need.
This is what I’m doing, using Json.NET:

[OperationContract]
        public string DoWork()
        {
            using (X ent = new X())
            {
                var modules = from p in ent.Modules select new { Name = p.Name, Value = p.ID };
                return JsonConvert.SerializeObject(modules);
            } 
        }

Now this is my javascript which renders the result inside a table:

function btn_onclick() {
            var srv = new DDSProjectManagement.ProjectsService();
            srv.DoWork(Res, null, null);
        }
        function Res(dataList) {
            var divObj = document.getElementById('tablePos');

            var name = 'Name';
            var desc = 'Description';

            var tableStart = '<table><tbody><tr><th>Name</th><th>Description</th></tr>';
            var tableContent = '';
            var tableEnd = '</tbody></table>';

            for (var i = 0; i < dataList.length; i++) {
                tableContent += '<tr><td>' + dataList[i].Name + '</td><td>' + dataList[i].Value + '</td></tr>';
            }
            divObj.innerHTML = tableStart + tableContent + tableEnd;
        }

If I do this, the parameter javascript gets is just a string and it is not able to see it as a list of my objects. Of course, it should be a Json string and I could try to parse it such that it extracts the objects from it. But I really want to use the javascript as it is now and modify the service. For example, changing my service in the following will work just fine:

public List<SimpleObject> DoWork()
        {                
            return new List<SimpleObject>() { new SimpleObject("Florin", 1), new SimpleObject("Andrei", 2) };
        }

SimpleObject is not an EntityFramework object so this has no problem. I suppose the default serializer is a Json one and javascript should get basically the same parameter: a Json string.

So my question is how do i make my method send a list of anonymous type objects to my JS as building the string via Json.NET didn’t work?
Thanks in advance.

Answer 1

This finally worked for me. The return type of the method is Stream and here is how it works:

    public Stream GetModules()
            {
                using (PMEntity ent = new PMEntity())
                {                
                    List<Module> ret = new List<Module>();
                    ret = ent.Modules.Include("Project").ToList();

                    return new MemoryStream(
                            Encoding.UTF8.GetBytes(
                            JsonConvert.SerializeObject(
                            ret.Select(e => new { Name = e.Name, Value = e.ID }))));
                }
            }